Intelligent dimming lighting

ABSTRACT

Systems, devices, and techniques are provided for operating a display and/or an illumination source based upon the direction of a user&#39;s gaze and/or a desired illumination level in a monitored area. One or more elements may be controlled with sensor input and application lighting preferences. For example, when a user receives a video call, light may be activated to illuminate their face. When the user is looking at the display, the display will be at the brightness necessary for the lighting conditions. When the user looks away from the screen, the screen may dim further and the lighting elements for the desk can brighten. Similarly, embodiments may adjust the lighting in a monitored location based upon lighting levels identified in other areas.

The claimed invention was made by, on behalf of, and/or in connectionwith one or more of the following parties to a joint universitycorporation research agreement: Regents of the University of Michigan,Princeton University, The University of Southern California, and theUniversal Display Corporation. The agreement was in effect on and beforethe date the claimed invention was made, and the claimed invention wasmade as a result of activities undertaken within the scope of theagreement.

FIELD OF THE INVENTION

The present invention relates to intelligent dimming lights and lightingsystems and, more specifically, to lighting systems that include OLEDillumination sources.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting devices (OLEDs), organic phototransistors, organic photovoltaiccells, and organic photodetectors. For OLEDs, the organic materials mayhave performance advantages over conventional materials. For example,the wavelength at which an organic emissive layer emits light maygenerally be readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Color may be measured using CIE coordinates, which are wellknown to the art.

One example of a green emissive molecule is tris(2-phenylpyridine)iridium, denoted Ir(ppy)₃, which has the following structure:

In this, and later figures herein, we depict the dative bond fromnitrogen to metal (here, Ir) as a straight line.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processible” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

SUMMARY OF THE INVENTION

Embodiments of the invention provide luminaires, lighting systems, andrelated systems and techniques that allow for control of illumination ofone or more areas. In an embodiment, a system may include a display; anillumination source; a gaze direction sensor such as a camera; and atleast one controller in communication with the display and theillumination source, which is configured to control of at least one ofthe display and the general illumination source based upon a signalreceived from the gaze direction sensor. The controller also may beconfigured to control each of the display and the general illuminationsource based upon the signal. The controller also may be configured tocontrol the display at a different rate of change than the generalillumination source, and/or each of the display and the generalillumination source may be configured to change state at a differentrate, in response to an instruction from the controller. In anembodiment, the illumination source may be transparent, flexible, orboth transparent and flexible.

The illumination source may be, for example, an organic light emittingdevice. Various components may be physically grouped or integrated. Forexample, the electronic device may include both a display and a gazedirection sensor, and the second electronic device may include theillumination source and the controller. As another example, the display,the illumination source, the gaze direction sensor, and the controllerare disposed in a single physical device, or each of the display, theillumination source, the gaze direction sensor, and the controller maybe a physically separate device. Each component may communicatewirelessly with any other component in the system. More specifically,the controller may be in wireless communication with the display, theillumination device, the gaze direction sensor, or combinations thereof.

The system may include one or more general-purpose computers, such asmobile computing devices including smartphones, tablets, or the like,and one or more luminaires, where the general-purpose computer(s)include the display and the gaze direction sensor, and the lampcomprises the illumination source. The general-purpose computer also mayinclude the controller.

In an embodiment, multiple illumination device are capable of beingcontrolled by the at least one controller.

In an embodiment, one or more illumination sources may be color-tunable,and the controller may be configured to control the color of lightemitted by the illumination source in response to the signal.

In an embodiment, the at least one controller is configured to controlthe color temperature of a white point of the display in response to thesignal.

In an embodiment, a luminaire includes a communication module configuredto receive a signal from an external device, which indicates a directionof a gaze of a user; an illumination source; and a controller configuredto control the illumination source based upon the signal. The luminairealso may include a sensor, configured to determine the gaze of the user.The illumination source may include an organic light emitting device.

In an embodiment, a device includes a gaze direction sensor configuredto determine a gaze direction of a user; and a controller configured tocontrol an external illumination source based upon the gaze direction,where the external illumination source is physically separate from thedevice.

In an embodiment, a device may include a display; a gaze directionsensor configured to determine a gaze direction of a user; and acommunication module configured to send a signal to an illuminationsource, where the signal indicating the gaze direction. The illuminationsource may be physically distinct from the display. The device may be aportable computing device. The illumination source may be physicallyattached to the display, and may be configurable in a collapsed orexpanded state.

In an embodiment, a system may include a local illumination source; ageneral room illumination source; a light sensor configured to measure alevel of illumination in a region; an da controller configured toreceive a signal from the light sensor, and to control at least one ofthe local illumination source and the general room illumination sourcebased upon the signal, to produce a selected illumination level in theregion. The light sensor may be physically separate from the localillumination source and from the general room illumination source. Thelight sensor may include essentially a solar cell, a wirelesstransmitter, and circuitry configured to provide a level of detectedillumination via the wireless transmitter.

In an embodiment, a controller may be configured to adjust the generalroom illumination source such that, when a local illumination source ison, the general illumination source is operated at a level that is notmore than 50% of the illumination intensity at which it is operated whenthe local illumination source is off.

In an embodiment, the controller may be configured to adjust the generalroom illumination source such that, when the local illumination sourceis on, the energy consumption of the overall system is less than 50% ofthe energy consumption of the overall system compared to when the localillumination source is off.

In an embodiment, the controller may be configured to adjust the generalroom illumination source such that, when the local illumination sourceis on, the energy consumption of the overall system is less than 30% ofthe energy consumption of the overall system compared to when the localillumination source is off. The local illumination source may have apeak intensity <5,000 cd/m² at any point on its emitting surface.

In an embodiment, an indication of a gaze direction of a user may bereceived from a gaze direction sensor, and a general illumination sourcemay be controlled based upon the indication of the gaze direction.Similarly, a display may be controlled based upon the indication of thegaze direction. It may be controlled at the same as, or at a differentrate as the general illumination source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

FIGS. 3A-3D shows example devices and arrangements for controllingelectronic devices based upon a user's gaze according to embodiments ofthe invention.

FIGS. 4A-4B show example devices according to embodiments of theinvention.

FIG. 5 shows an example of a workspace including lighting systemsaccording to an embodiment of the invention.

FIG. 6 shows an example of multiple workspaces including lightingsystems according to an embodiment of the invention.

FIG. 7 shows an example schematic representation of a system including acontroller and multiple illumination sources according to an embodimentof the invention.

FIG. 8 shows an example system that includes a gaze sensor and anillumination level sensor according to an embodiment of the invention.

FIG. 9 shows a perspective view of a room that includes a systemaccording to an embodiment of the invention.

FIG. 10 shows illustrative room arrangements and associated energycalculations for different lighting configurations according to anembodiment of the invention.

DETAILED DESCRIPTION

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75. No. 3, 4-6 (1999) (“Baldo-II”), which are incorporatedby reference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, a cathode 160, and a barrier layer 170.Cathode 160 is a compound cathode having a first conductive layer 162and a second conductive layer 164. Device 100 may be fabricated bydepositing the layers described, in order. The properties and functionsof these various layers, as well as example materials, are described inmore detail in U.S. Pat. No. 7,279,704 at cols. 6-10, which areincorporated by reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F₄₋TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. Pat. No. 7,431,968, which is incorporated by reference in itsentirety. Other suitable deposition methods include spin coating andother solution based processes. Solution based processes are preferablycarried out in nitrogen or an inert atmosphere. For the other layers,preferred methods include thermal evaporation. Preferred patterningmethods include deposition through a mask, cold welding such asdescribed in U.S. Pat. Nos. 6,294,398 and 6,468,819, which areincorporated by reference in their entireties, and patterning associatedwith some of the deposition methods such as ink-jet and OVJP. Othermethods may also be used. The materials to be deposited may be modifiedto make them compatible with a particular deposition method. Forexample, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20 carbons isa preferred range. Materials with asymmetric structures may have bettersolution processibility than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the presentinvention may further optionally comprise a barrier layer. One purposeof the barrier layer is to protect the electrodes and organic layersfrom damaging exposure to harmful species in the environment includingmoisture, vapor and/or gases, etc. The barrier layer may be depositedover, under or next to a substrate, an electrode, or over any otherparts of a device including an edge. The barrier layer may comprise asingle layer, or multiple layers. The barrier layer may be formed byvarious known chemical vapor deposition techniques and may includecompositions having a single phase as well as compositions havingmultiple phases. Any suitable material or combination of materials maybe used for the barrier layer. The barrier layer may incorporate aninorganic or an organic compound or both. The preferred barrier layercomprises a mixture of a polymeric material and a non-polymeric materialas described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos.PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporatedby reference in their entireties. To be considered a “mixture”, theaforesaid polymeric and non-polymeric materials comprising the barrierlayer should be deposited under the same reaction conditions and/or atthe same time. The weight ratio of polymeric to non-polymeric materialmay be in the range of 95:5 to 5:95. The polymeric material and thenon-polymeric material may be created from the same precursor material.In one example, the mixture of a polymeric material and a non-polymericmaterial consists essentially of polymeric silicon and inorganicsilicon.

Devices fabricated in accordance with embodiments of the invention maybe incorporated into a wide variety of consumer products, including flatpanel displays, computer monitors, medical monitors, televisions,billboards, lights for interior or exterior illumination and/orsignaling, heads up displays, fully transparent displays, flexibledisplays, laser printers, telephones, cell phones, personal digitalassistants (PDAs), laptop computers, digital cameras, camcorders,viewfinders, micro-displays, 3-D displays, vehicles, a large area wall,theater or stadium screen, or a sign. Various control mechanisms may beused to control devices fabricated in accordance with the presentinvention, including passive matrix and active matrix. Many of thedevices are intended for use in a temperature range comfortable tohumans, such as 18 degrees C. to 30 degrees C., and more preferably atroom temperature (20-25 degrees C.), but could be used outside thistemperature range, for example, from −40 degree C. to +80 degree C.

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

The terms halo, halogen, alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl,heterocyclic group, aryl, aromatic group, and heteroaryl are known tothe art, and are defined in U.S. Pat. No. 7,279,704 at cols. 31-32,which are incorporated herein by reference.

A modern personal workspace often may contain both a computer displayand an illumination source such as a task lamp. The “desk top” in theworkspace typically includes both real and virtual environments, eachwith differing requirements for lighting. For example, a real desktop isusually horizontal and illuminated by a variety of illumination sources,whereas a virtual “desktop,” typically provided by one or more displays,is often self-illuminating and nearer to vertical. Often, both a displayand an illumination source such as a luminaire will be turned on and atfull brightness even though the user typically will use only one or theother at any given moment. Embodiments of the present invention mayprovide energy-saving systems and devices that incorporate a display orsimilar device and an illumination source that operate in coordinationwith each other and with a sensor that determines whether or not theuser is looking at the display screen. For example, when the user islooking at the display, the display may be at fiull brightness or at an“in use” brightness setting and the luminaire may be automaticallydimmed. Similarly, when the user looks away from the display, thedisplay may dim and the luminaire may return to full brightness. Inaddition, the workspace may be illuminated by ceiling and/or overheadlighting that may be controlled with, or instead of, a task lamp orsimilar luminaire or other local illumination source.

More generally, the illumination available at a workstation may includelight from many sources, such as a task lamp, general room illuminationsources such as overhead lighting, and other ambient sources.Embodiments of the present invention may provide techniques and systemsto maintain a specified light level at a work surface by adjusting oneor more of these sources.

Example systems disclosed herein may include one or more lightingelements that can be controlled with sensor input and applicationlighting preferences. As a specific example, when a user receives avideo call, a light may be activated to illuminate the user's face.Sensors can determine whether or not the user is currently looking at adisplay screen. When the user is looking at the display, the displaywill be at the brightness necessary for the lighting conditions. Suchconditions may not require the display to be as bright as if the desk isfully illuminated (for, e.g., increased contrast). When the user looksaway from the screen, the screen may dim further and the lightingelements may brighten, in some cases only in the direction of the user'sattention. The lighting elements may include a task light or similarlight source positioned relatively close to the workspace, overheadillumination such as ceiling or similar light sources, or combinationsthereof.

As another example, a sensor may monitor the light level on a worksurface. When the light sensor registers no other light sources arepresent at the surface, a controller may increase the level ofillumination provided by a general illumination source such as anoverhead light to a full brightness level, thus providing all of thelight needed to maintain the light sensor's preset threshold. If anotherlight source, such as daylight from a window or illumination from a tasklight, provides some light to the surface but not a level above thelight sensor's threshold, the general room lights may be adjusted toprovide just enough light to compensate. If a local task lamp is on andis providing enough light to reach the light sensor's threshold, thegeneral room lights may dim to a minimum preset level, which could be atzero luminance.

Embodiments disclosed herein may save energy and allow forpersonalization of the lighting levels proximal to individual users,responding to their activities and adjusting the balance between lightprovided by a display, the light provided by an illumination source suchas a personal desk light, and/or the light provided by a general roomillumination source such as an overhead light.

Generally, embodiments disclosed herein can include several components:a display such as a computer display, an illumination source such as atask lamp or other local light source in proximity to the display, oneor more sensors that can determine the level of light in a work areaand/or the direction of a user's gaze, i.e., in which direction and/orwhere on a surface or other location the user is looking, a general roomillumination source, and a control system such as one or more localcontrollers which can adjust the display and the illumination source,such as to independently raise and lower the brightness level of each,change the color temperature of each, or change the general coloring ofthe illumination source. For example, when the sensor determines theuser is looking at the display, the controller may raise the brightnesslevel of the display and lower the brightness level of the illuminationsource, and when the sensor determines that the user is not looking atthe display, the controller may lower the brightness level of thedisplay and raise the brightness of the light source.

The reaction time of the system, i.e., the rate of change at which thecontroller changes operation of the display and/or the illuminationsource, may have an effect on user comfort. For example, rather thandimming and brightening instantly as the user looks at and away from thedisplay, it may be preferable for there to be a built-in delay. Thedelay may cause the intensity changes to be less jarring or evenunnoticeable to the user. Different components may have differentdelays, i.e., different rates of change or delays before a changeoccurs. For example, when a user is looking at a display, theillumination source may not begin to dim for about a minute, after whichthe dimming may occur very slowly, for example over a 10 minute period,after which the source is at a minimum brightness. When the user thenlooks away from the display, the illumination source may brightenrelatively quickly, but still may take at least 1 or 2 seconds toachieve full brightness. The dimming and brightening of the display maybe less jarring and often may occur more quickly, but it may bepreferable to have a delay of, for example, 30 seconds before thedisplay begins to dim. Similarly, it may be preferred for the display tobrighten relatively quickly, for example in less than 1 second.

OLED components may be particularly well-suited for the illuminationcomponents disclosed herein, but may also be used for a display. OLEDsprovide an inherently low heat, no glare, and dimmable light source,allowing a component to be placed in close proximity to the user, andthus may provide a desirable source of task lighting. In configurationswhere a color-tunable OLED is used, an illumination source as disclosedherein may shift into the warmer, redder end of the spectrum when itdims. It is generally understood that people often prefer light sourcesthat become warmer as they dim, such as incandescent bulbs and otherblackbody radiators. This effect also may serve to increase the overalllifetime of the OLED since blue emitters, which typically have lowerlifetimes than other emitters, would be conserved. Similarly, when asensor detects that the user is not looking at the display, the displaymay dim. If the display is an OLED or similar display, the display alsomay reduce the color temperature of the display white point so as tofurther reduce power consumption and/or extend the display lifetime.Devices typically are designed to have a specific white point colortemperature, which may be user-adjustable, commonly in the range of6,000-10,000 K, which corresponds to bluish-white.

The rate of change, color temperature and color, and any other aspectsof the illumination source and/or the display may be controlled by thecontroller, or they may be inherent to the components. For example, acontroller may specify a brightness at which an illumination source isto operate, and a time over which the source should change state from acurrent state to the indicated brightness. Alternatively, the controllermay send a simple instruction either to brighten or dim, or to operateat a specific brightness, at which point the illumination source mayoperate using built-in parameters to achieve the specified operationstate.

An illumination source as disclosed herein may have various physicalarrangements and properties. For example, the illumination source mayinclude transparent and/or flexible components, and may be flexibleand/or transparent as a whole. For example, a flexible task lamp may beused that can be positioned along a desired contour of a work area. Theillumination source also may be physically connected to the displayand/or other components of the system. For example, the illuminationsource may be configurable in a collapsed state, such as where it isfolded into or against the display, and in an expanded state, in whichit extends away from the display to provide illumination to a differentregion of a work area. The illumination source also may be relativelythin, for example, not more than 3 mm thick. More generally,illumination sources disclosed herein may have any energy profiles,physical dimensions, power requirements, and other attributes that areachievable for OLED and similar types of lighting systems. For example,PHOLED or other OLED devices may be used. A local task light asdisclosed herein may have a peak intensity less than 5,000 cd/m² at anypoint on the emitting surface. It also may contain no hazardousmaterials, and may be capable of producing at least 50 lm/W at a CRI of80 or more under normal operating conditions.

The four components may be arranged in different ways as shown in FIG.3. Generally, unless disclosed herein, each component may communicatewith any other component via any suitable wired or wireless connectionand protocol. Typically, a controller 340 receives information from thesensor 320, and provides control information to, or otherwise controls,the display 310 and illumination source 330, for example as shown inFIG. 3. More generally, any other arrangement of information flow amongthe components may be used, and other intermediary components may beincluded. For example, where the display and/or sensor is integratedwith a computing device, the computing device may receive informationfrom the sensor and relay it to the controller, or it may receivecontrol signals from the controller and relay appropriate controlsignals to the display and/or sensor.

As previously described, a controller may receive information from agaze direction sensor that indicates a direction, region, or location atwhich a user is looking. Based upon this information, the controller maycontrol the display, the illumination source, or both. The control mayinclude changing the brightness of the display and/or illuminationsource, such as to dim the component not in use by the user. The controlalso may include changing the color temperature or apparent color of thecomponent, such as to change the color temperature of light emitted bythe illumination source or the display.

FIG. 3A shows an example arrangement in which each component isphysically separate. In such an arrangement, the controller 340 maycontrol the display 310 and illumination source 330 based upon gazedirection information obtained by the sensor 320, which indicates wherea user is looking. Although physically separate in the example shown inFIG. 3A, the components may be arranged in proximity to one another,including in direct physical contact. For example, the sensor 320 mayinclude a camera that is placed on or attached to the display 310 or theillumination source 330.

More preferably, the components may be combined in various ways. FIG. 3Bshows an example configuration in which the sensor 320 is combined withthe display 310 within a first device 301 such as a general purposecomputer or a computer monitor, and the controller 340 is combined withthe illumination source 330 in a second device 302 such as a luminaire.Although shown in a monitor and luminaire as an example arrangement, itwill be understood that the devices 301 and 302 may be any suitabledevices. Such arrangements may be useful to take advantage of existingcomponents of these devices. For example, many displays include abuilt-in camera that may operate as the gaze direction sensor. Combiningthe controller with the illumination source in a device such as a lampalso may allow the user to easily override an automatic dimming or otherchange initiated by the controller. As previously described, thecontroller 340 may control the illumination source 330 based upon asignal from the sensor 320. In this example, the display 310 may becontrolled by one or more other components within the device 301, or itmay be controlled by the controller 340 within the second device 302.

FIG. 3C shows an arrangement in which all the components are integratedwithin a single device 304, such as a general purpose computer. Forexample, the sensor may be implemented by a camera within the device304, and may provide gaze direction information to a processor withinthe device as previously described. The processor may operate as thecontroller 340 to control a display 310 and illumination source 330. Thedisplay may be, for example, a conventional display of a general-purposecomputer system. The illumination source may be, for example, a lightcontained within or disposed upon a housing of the device 304.

FIG. 3D shows another example configuration in which the display 310 andthe controller 340 are implemented within one device 305, such as acomputer monitor, and the sensor 320 and illumination source 330 areimplemented within a second device, such as a lamp or other luminaire.Such a configuration may be useful to allow a user to obtain only asingle new device, such as an illumination/sensor device 306, which canthen interface with an existing computer, monitor, or other device 305already owned by the user. The device 305 may be configured to providefunctionality of the controller 340 and/or display 310 via, for example,software installed on or executed by a processor of the device 305.

FIGS. 3A-3D show specific examples of arrangements of the basic systemcomponents disclosed herein. However, any suitable arrangement of thecomponents may be used without departing from the scope and content ofthe present disclosure.

In some configurations, there may be more than one of any of thecomponents described herein. For example, in an embodiment a mobilephone or other device which includes a display and camera sensor couldbe wirelessly connected to the controller, or the controller could beconnected to multiple luminaires. Such a system may allow for moreprecise tracking of the user's gaze, where multiple sensors are used todetermine the direction of the user's gaze. As another example, a systemwhich includes or controls multiple illumination sources may allow forcontrol of ambient or other lighting within a larger area such as a roomhaving multiple luminaires as disclosed herein, or the like.

FIG. 4A shows a schematic representation of an example illuminationsource 400 as disclosed herein, such as a task lamp or other luminaire.The luminaire includes an illumination source 410 and a communicationmodule 420 which may receive information from an external sensor and/orcontroller. The information may be provided to a controller 430, whichmay then control the illumination source as previously disclosed.Alternatively or in addition, the illumination source 410 may becontrolled directly by an external controller, or primarily by anexternal controller operating via a local controller 430. Multiplecontrollers and/or sensor signals may be received by the luminaire andused to control the illumination source. As previously described, theluminaire also may include one or more sensors, such as a gaze directionsensor, to determine a direction or region at which the user is looking.The illumination source 410 may be an OLED or any other suitablelight-emitting component as previously described.

FIG. 4B shows an example device 450 that includes a gaze directionsensor 460 and a controller 470. The device 450 may be, for example, acamera that is external to a display and/or an illumination source, acamera that is integrated with a display or other device, a portablecomputing device such as a mobile phone, or the like. As previouslydescribed, the controller may provide information to, and/or directlycontrol, an illumination source that is physically separate from thedevice 450. The device 450 also may include a display, communicationmodule, and other components as previously described.

FIG. 5 shows an example arrangement of a system disclosed herein at auser workstation. The system includes a camera 510 that is integratedwith a computer monitor 520 and a task lamp 530. As previouslydescribed, the camera may obtain user gaze direction information, whichis then used to control the monitor 520 and task lamp 530. Each of themonitor 520 and task lamp 530 may be controlled in any manner describedherein, including by adjusting the brightness of each, alone or intandem, changing the color temperature, and so on. FIG. 6 shows anarrangement that includes multiple workstations such as shown in FIG. 5,with each having an associated monitor and task light in the form ofOLED light sources. Notably, each workstation may have one or moreillumination sources that is linked to the monitor and sensor for thatworkstation, such that the illumination sources respond only to gazedirection information from the appropriate sensor.

The examples described above with respect to FIGS. 3-6 are provided interms of a gaze direction sensor and a display operating in conjunctionwith one or more sources of illumination. More generally, a sensor suchas a light level sensor may operate in conjunction with a controller andone or more illumination sources as previously described, to maintain adesired level of illumination at a particular location, such as a worksurface.

In an embodiment, a system may include a general room illuminationsource such as one or more ceiling or other overhead lights, a localillumination source such as a desk lamp or other task light, a lightsensor, and a controller that can communicate with and control thegeneral illumination source and the local illumination source. FIG. 7shows an example schematic representation of such a system. As with theother example systems shown, it will be understood that each light mayinclude a separate controller that communicates with other controllersand/or a sensor, or the system may include a single controller thatcommunicates with and controls multiple illumination sources. In theexample system shown in FIG. 7, a sensor 710 may detect the level oflight present in a specific area, such as a work surface. The sensor maybe configured to send a signal to a controller 740 if the level ofillumination in the area exceeds a threshold, or it may merely providean indication of the level of illumination in the area to thecontroller. The controller 740 may determine a level of illumination forone or more of the local and general lights 720, 730, respectively, tomaintain a desired level of illumination in the area monitored by thesensor 710. Thus, for example, if a user has indicated that themonitored area should be maintained at an illumination of 200 lux andthe local light 720 is providing 150 lux, the controller may adjust thegeneral illumination light to a level at which 50 lux is provided to themonitored area, i.e., so that the total level detected by the sensor 710is 200 lux. The sensor also may measure the light exitance of the worksurface, rather than measuring the illumination directly. Such aconfiguration may be desirable, for example, to allow the light sensorto be incorporated into a general room illumination luminaire ratherthan being placed directly on the work surface, from where it canmeasure the light reflected from the work surface. This measurement maythen be used as the measurement of the level of illumination in themonitored area, i.e., at the work surface.

It may be desirable for the local light 720 and other task lightsdisclosed herein to use OLED technology. Because of the properties ofOLED lighting (e.g., cool to touch, no glare and pleasing spectrum andlight quality) OLED luminaires can be used to provide more local lightthan other technologies—this means that less light is required from thefixture luminaires, and so this approach may provide the greatest energysavings. As described in further detail herein, the use of OLEDluminaires and other components may provide up to a 50% system energysavings can be preferably realized by OLED task lighting and none ofthis is discussed in the '552 application. We provide support in thesubmitted calculations.

The system shown in FIG. 7 also may include a gaze sensor as previouslydescribed. Thus, the level of light in a monitored area such as a worksurface may be set at one level when a user is looking at the worksurface, and another level when the user is looking away from the worksurface, such as toward a display as previously described. The level ofillumination provided in a monitored area may be set by the user, or itmay be predetermined. An example system that includes a gaze sensor andan illumination level sensor is shown in FIG. 8. As previouslydescribed, the gaze sensor 320 may determine the direction of a user'sgaze and communicate related information to the controller 340.Similarly, an illumination level sensor 710 may detect the level oflight in an area such as the work surface as previously described, andcommunicate related information to the controller 340. The controllermay then set appropriate illumination levels of one or more lights 330,730 and/or a display 310, as previously described. The controller may bea physically-separate device, or it may be integrated with the display,a computer, a lighting system, a light switch, or other component aspreviously described. Similarly, each of the sensors 320, 710 may beincorporated into another component of the system, such as a local tasklamp or other local illumination source, a general room illuminationluminaire, a display, a computer system, or the like.

FIG. 9 shows a perspective view of a room that includes a systemaccording to an embodiment of the invention. The room may include one ormore general illumination sources 910, a task light 930, a sensor 940,and a light switch 920. As previously disclosed, one or more of thelight switch 920 and lighting components 910, 930 may include acontroller that adjusts the level of illumination provided by eachlighting component 910, 930 based upon data received from the sensor940.

Embodiments of the invention may be implemented as components suitablefor interfacing with, or augmenting, existing lighting systems. Forexample, in an embodiment, a system may incorporate existing general andtask lighting. A small wireless light sensor may be placed on the user'sdesk and a replacement wall switch or controller that controls thegeneral room lighting may be installed in a room, such as in an existinglight switch wall receptacle. The light sensor may have relatively verylow power requirements, so that it may be powered by, for example,ambient light through the incorporation of photovoltaic cells, and thusrequire little or no user maintenance and/or external wired connections.

Systems and devices as disclosed herein also may adjust illuminationlevels of one or more illumination sources to achieve certain levelsrelative to one another. For example, the system may adjust a generalillumination source such that, when a local task light is on, thegeneral illumination source is operated at a level that is not more than50% of the illumination intensity at which it is operated when the tasklight is turned off. Similarly, the system may be configured that whenthe task lighting is on, the energy consumption of the overall system(task lighting plus general illumination) is less than 50% of the energyconsumption compared to when the task lighting is turned off.

Many work areas, such as offices and work rooms, use non-dimmablefluorescent lights. In an embodiment, a wireless light sensor may bepaired with dimmable retrofit general illumination lights such as LEDlights. The LED lights may replace fluorescent luminaires, (troffers),or they may be tubular linear LED lamps that fit into existing troffersand replace only the florescent tube. The advantage of tubular LED lampsis that the user would not need to do anything complicated such asinstalling new wiring to complete a retrofit installation, merelyreplace existing fluorescent tubes with the LED tubes and place thewireless sensor on their desk. However, tubular LEDs may not be asefficient as replacement LED troffers.

In an embodiment, OLED luminaires such as task lamps and LED ceilinglights designed for new construction, rather than retrofitting, may beused. Such systems may operate in a similar fashion to those described,but may be more desirable for new construction or in situations wherenew lighting systems are being installed.

Communications other than those specifically described may be performedbetween the sensors, controller, and/or illumination sources. Forexample, in an embodiment, a task light or other local illuminationsource may communicate with a general illumination source, directly orvia a controller, to inform the general illumination source that thetask light is turned on. Thus it may be determined whether the tasklight is operational, and the general illumination source may adjust itsown output based on this communication. Similarly, a controller mayreceive information regarding the operational status of one or moreillumination sources, including local lights, general room lights,specialty-purpose lights, and the like, and adjust the output of one ormore of the illumination sources to achieve a desired illumination levelin a monitored area.

It may be possible to implement the light sensor and other componentsdisclosed herein using relatively low power communications. For example,an illumination level sensor as disclosed may be operable using alow-power wireless communication protocol such as Bluetooth® or asimilar technique. The sensor also may be powered by an embedded solarcell and/or internal battery. A low-power Bluetooth® transmitterrequires approximately 45 μJ per transmission burst. A 1 cm² solar celloperating at 10% efficiency can produce approximately 0.04 mW at 500 luxillumination. Thus, a solar cell should provide sufficient energy toallow approximately 1 transmission burst each second.

Notably, the use of a relatively small, physically-distinct light sensormay be more desirable than configurations in which a sensor may beintegrated with a task lamp or other component. In a configuration inwhich the sensor is separate, it may record the light incident on asurface of interest, including any light from the task lamp. Embodimentsof the present invention may maximize energy savings by reducing generalroom illumination fixture lighting dependent on light coming from othersources such as daylight or a task lamp, as the fixture lightingtypically has the lowest application efficiency due to its largerdistance from the work surface and therefore typically is the leastefficient. Thus, it may be desirable to rely primarily on the local tasklighting to reduce the need for the use of lower efficiency fixturelighting.

Embodiments disclosed herein may provide for additional energy usereductions. For example, FIG. 10 shows illustrative room arrangementsand associated energy calculations for configurations that use allfluorescent lamps, LED-only lamps, LED/OLED lamps and only OLED lamps.One office 1010 includes all fluorescent lighting. A second office 1020includes ceiling illumination. A third office 1030 includes LEDs thatprovide ceiling illumination and OLEDs used as task lighting and placedcloser to a user. Finally, in Office 4 4040 the OLED lighting is usedboth as ceiling lighting and task lighting. As shown, the OLED andLED/OLED configurations are expected to provide equivalent illuminationat a much lower energy expenditure.

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

1-40. (canceled)
 41. A system comprising: a local illumination source; ageneral room illumination source; a light sensor configured to measure alevel of illumination in a region; and a controller configured toreceive a signal from the light sensor, and to control at least one ofthe local illumination source and the general room illumination sourcebased upon the signal, to produce a selected illumination level in theregion.
 42. The system of claim 41, wherein the light sensor isphysically separate from the local illumination source and from thegeneral room illumination source.
 43. The system of claim 41, whereinthe light sensor consists essentially of a solar cell, a wirelesstransmitter, and circuitry configured to provide a level of detectedillumination via the wireless transmitter.
 44. The system of claim 41,wherein the controller is configured to adjust the general roomillumination source such that, when the local illumination source is on,the general illumination source is operated at a level that is not morethan 50% of the illumination intensity at which it is operated when thelocal illumination source is off.
 45. The system of claim 41, whereinthe controller is configured to adjust the general room illuminationsource such that, when the local illumination source is on, the energyconsumption of the overall system is less than 50% of the energyconsumption of the overall system compared to when the localillumination source is off.
 46. The system of claim 41, wherein thecontroller is configured to adjust the general room illumination sourcesuch that, when the local illumination source is on, the energyconsumption of the overall system is less than 30% of the energyconsumption of the overall system compared to when the localillumination source is off. 47-50. (canceled)